Plasma Display Panel (PDP)
While research proceeded on HDTV systems around the time of the Tokyo Olympics, it was noted that HDTV broadcasting would be promoted if a thin, lightweight, and large-display system could be developed. STRL initiated studies on a large flat display suitable for HDTV broadcasting around 1971. Its research engineers first examined the possible types of flat display, investigating liquid crystal (LCD), electroruminescent (EL), or light emitting diodes (LED), before proceeding with research on PDP, based on their decision that PDP would be at the shortest path to realizing a large, flat display.
The luminous principle for PDP, similar to that of fluorescent light, utilizes a luminous discharge phenomenon. The idea to construct a display by aligning multiple small fluorescent lights is rather old; the first PDP was test manufactured in the United States at the beginning of 1960’s. However, the initial PDP’s luminance was so poor that it could barely displayed textual data, and only in orange. Another significant technical problem was the need to expand the display size for HDTV broadcasting.
STRL developed phosphors that emits the three primary colors of red/blue/green and a filler gas appropriate for each one. The PDP system fabricated then still had a very dark screen. Therefore, a continuous effort was made to improve the luminance; the PDP structure was improved by incorporating a memory driving method to extend luminous time, and a white barrier and reflecting fluorescent screen that can efficiently derive generated light were developed. This resulted in a practical luminance level for implementation.

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On the other hand, a new, unconventional development technique was needed to realize the large display. In the case of PDP, research started with a display size target of 40inches or larger, requiring development of a large PDP manufacturing device as the first step. STRL pioneered large PDP manufacturing device development, constructing the world’s first 40-inch color PDP system. It also participated in the Hi-Vision PDP Development Consortium, greatly contributing to realization of a large PDP system.
Future PDP system research will aim at brighter, lower power consumption, higher definition, and larger displays. The display engineers’ dreams will ultimately grow into a display that covers an entire wall and whose physical body is insubstantial.

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